feat(P4): IHF Phase 4 complete — Outcome Observation and Antifragility Loop

Closes the IHF improvement loop. Full antifragility chain now traversable:
Widget → Annotation → Candidate → Requirement → Decision → Deployment → OutcomeSignal

New artifacts:
- DeploymentRecord (immutable, links DecisionRecord to a deployed version)
- OutcomeSignal (append-only; DB trigger prevents UPDATE/DELETE)
- ChangeEvaluation (one-per-deployment; UNIQUE constraint; 1–5 score)

New capabilities:
- DeploymentRecordsController (index, show, new, create)
- RecordOutcomeSignalAction — capture improved/regressed/neutral/inconclusive signals
- Pre/post comparison panel on deployment show (±30-day event/annotation counts)
- Regression detection — improved signal followed by high/critical annotation
- ChangeEvaluation — idempotent score+rationale per deployment
- Recurrence tracking — cycle count per widget, leaderboard
- AntifragilityDashboardAction (autoRefresh, 5 panels) per hub
- Phase 4 integration tests (T01–T08 logic coverage)
- docs/phase4-summary.md; SCOPE.md updated to Phase 4 complete

State Hub: workstream 07e9c860 → completed

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Web/Controller/Widgets.hs

@@ -9,6 +9,7 @@ import Generated.Types
 import IHP.Prelude
 import IHP.ControllerPrelude
 import Data.Aeson (toJSON, object, (.=))
+import Application.Helper.Controller (isInRegression, widgetCycleCounts)
 
 instance Controller WidgetsController where
     beforeAction = ensureIsUser
@@ -39,7 +40,23 @@ instance Controller WidgetsController where
             |> filterWhere (#widgetId, widgetId)
             |> orderByAsc #createdAt
             |> fetch
-        render ShowView { widget, hub, versions, events, annotations }
+        recentSignals <- query @OutcomeSignal
+            |> filterWhere (#widgetId, widgetId)
+            |> orderByDesc #observedAt
+            |> limit 10
+            |> fetch
+        allSignals <- query @OutcomeSignal
+            |> filterWhere (#widgetId, widgetId)
+            |> fetch
+        let isRegressed = isInRegression allSignals annotations widgetId
+        -- Recurrence cycle count for this widget
+        allCandidates  <- query @RequirementCandidate |> filterWhere (#sourceWidgetId, widgetId) |> fetch
+        allRequirements <- query @Requirement |> fetch
+        allDecisions   <- query @DecisionRecord |> fetch
+        allDeployments <- query @DeploymentRecord |> fetch
+        let cycleCounts = widgetCycleCounts allCandidates allRequirements allDecisions allDeployments
+            cycleCount  = fromMaybe 0 (lookup widgetId cycleCounts)
+        render ShowView { widget, hub, versions, events, annotations, recentSignals, isRegressed, cycleCount }
 
     action CreateWidgetAction = do
         let widget = newRecord @Widget